//
//  NSData+Base64.m
//  Froth
//
//  Created by Crystal Phillips on 29/06/09.
//
//  Copyright (c) 2009 Thinking Code Software Inc. http://www.thinkingcode.ca
//
//	Permission is hereby granted, free of charge, to any person
//  obtaining a copy of this software and associated documentation
//	files (the "Software"), to deal in the Software without
//	restriction, including without limitation the rights to use,
//	copy, modify, merge, publish, distribute, sublicense, and/or sell
//	copies of the Software, and to permit persons to whom the
//	Software is furnished to do so, subject to the following
//	conditions:

//	The above copyright notice and this permission notice shall be
//	included in all copies or substantial portions of the Software.

//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//	OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//	HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//	WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//	OTHER DEALINGS IN THE SOFTWARE.

#import "NSData+Utilities.h"
#include <zlib.h>
#include <openssl/md5.h>
#include <openssl/sha.h>
#include <openssl/ripemd.h>

static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

@implementation NSData (Base64)

+ (id)dataWithBase64EncodedString:(NSString *)string;
{
	if (string == nil)
		[NSException raise:NSInvalidArgumentException format:nil];
	if ([string length] == 0)
		return [NSData data];
	
	static char *decodingTable = NULL;
	if (decodingTable == NULL)
	{
		decodingTable = malloc(256);
		if (decodingTable == NULL)
			return nil;
		memset(decodingTable, CHAR_MAX, 256);
		NSUInteger i;
		for (i = 0; i < 64; i++)
			decodingTable[(short)encodingTable[i]] = i;
	}
	
	const char *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];
	if (characters == NULL)     //  Not an ASCII string!
		return nil;
	char *bytes = malloc((([string length] + 3) / 4) * 3);
	if (bytes == NULL)
		return nil;
	NSUInteger length = 0;
	
	NSUInteger i = 0;
	while (YES)
	{
		char buffer[4];
		short bufferLength;
		for (bufferLength = 0; bufferLength < 4; i++)
		{
			if (characters[i] == '\0')
				break;
			if (isspace(characters[i]) || characters[i] == '=')
				continue;
			buffer[bufferLength] = decodingTable[(short)characters[i]];
			if (buffer[bufferLength++] == CHAR_MAX)      //  Illegal character!
			{
				free(bytes);
				return nil;
			}
		}
		
		if (bufferLength == 0)
			break;
		if (bufferLength == 1)      //  At least two characters are needed to produce one byte!
		{
			free(bytes);
			return nil;
		}
		
		//  Decode the characters in the buffer to bytes.
		bytes[length++] = (buffer[0] << 2) | (buffer[1] >> 4);
		if (bufferLength > 2)
			bytes[length++] = (buffer[1] << 4) | (buffer[2] >> 2);
		if (bufferLength > 3)
			bytes[length++] = (buffer[2] << 6) | buffer[3];
	}
	
	realloc(bytes, length);
	return [NSData dataWithBytesNoCopy:bytes length:length];
}

- (NSString *)base64Encoding;
{
	if ([self length] == 0)
		return @"";
	
    char *characters = malloc((([self length] + 2) / 3) * 4);
	if (characters == NULL)
		return nil;
	NSUInteger length = 0;
	
	NSUInteger i = 0;
	while (i < [self length])
	{
		char buffer[3] = {0,0,0};
		short bufferLength = 0;
		while (bufferLength < 3 && i < [self length])
			buffer[bufferLength++] = ((char *)[self bytes])[i++];
		
		//  Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.
		characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2];
		characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];
		if (bufferLength > 1)
			characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];
		else characters[length++] = '=';
		if (bufferLength > 2)
			characters[length++] = encodingTable[buffer[2] & 0x3F];
		else characters[length++] = '=';	
	}
	
	return [[[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES] autorelease];
}

#pragma mark -
#pragma mark More

// http://www.cocoadev.com/index.pl?NSDataCategory

// Returns range [start, null byte), or (NSNotFound, 0).
- (NSRange) rangeOfNullTerminatedBytesFrom:(int)start
{
	const Byte *pdata = [self bytes];
	int len = [self length];
	if (start < len)
	{
		const Byte *end = memchr (pdata + start, 0x00, len - start);
		if (end != NULL) return NSMakeRange (start, end - (pdata + start));
	}
	return NSMakeRange (NSNotFound, 0);
}

+ (NSData *) dataWithBase32String:(NSString *)encoded
{
	/* First valid character that can be indexed in decode lookup table */
	static int charDigitsBase = '2';
	
	/* Lookup table used to decode() characters in encoded strings */
	static int charDigits[] =
	{	26,27,28,29,30,31,-1,-1,-1,-1,-1,-1,-1,-1 //   23456789:;<=>?
		,-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14 // @ABCDEFGHIJKLMNO
		,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1 // PQRSTUVWXYZ[\]^_
		,-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14 // `abcdefghijklmno
		,15,16,17,18,19,20,21,22,23,24,25                // pqrstuvwxyz
	};
	
	if (! [encoded canBeConvertedToEncoding:NSASCIIStringEncoding]) return nil;
	const char *chars = [encoded cStringUsingEncoding:NSASCIIStringEncoding]; // avoids using characterAtIndex.
	int charsLen = [encoded lengthOfBytesUsingEncoding:NSASCIIStringEncoding];
	
	// Note that the code below could detect non canonical Base32 length within the loop. However canonical Base32 length can be tested before entering the loop.
	// A canonical Base32 length modulo 8 cannot be:
	// 1 (aborts discarding 5 bits at STEP n=0 which produces no byte),
	// 3 (aborts discarding 7 bits at STEP n=2 which produces no byte),
	// 6 (aborts discarding 6 bits at STEP n=1 which produces no byte).
	switch (charsLen & 7) { // test the length of last subblock
		case 1: //  5 bits in subblock:  0 useful bits but 5 discarded
		case 3: // 15 bits in subblock:  8 useful bits but 7 discarded
		case 6: // 30 bits in subblock: 24 useful bits but 6 discarded
			return nil; // non-canonical length
	}
	int charDigitsLen = sizeof(charDigits);
	int bytesLen = (charsLen * 5) >> 3;
	Byte bytes[bytesLen];
	int bytesOffset = 0, charsOffset = 0;
	// Also the code below does test that other discarded bits
	// (1 to 4 bits at end) are effectively 0.
	while (charsLen > 0)
	{
		int digit, lastDigit;
		// STEP n = 0: Read the 1st Char in a 8-Chars subblock
		// Leave 5 bits, asserting there's another encoding Char
		if ((digit = (int)chars[charsOffset] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		lastDigit = digit << 3;
		// STEP n = 5: Read the 2nd Char in a 8-Chars subblock
		// Insert 3 bits, leave 2 bits, possibly trailing if no more Char
		if ((digit = (int)chars[charsOffset + 1] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		bytes[bytesOffset] = (Byte)((digit >> 2) | lastDigit);
		lastDigit = (digit & 3) << 6;
		if (charsLen == 2) {
			if (lastDigit != 0) return nil; // non-canonical end
			break; // discard the 2 trailing null bits
		}
		// STEP n = 2: Read the 3rd Char in a 8-Chars subblock
		// Leave 7 bits, asserting there's another encoding Char
		if ((digit = (int)chars[charsOffset + 2] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		lastDigit |= (Byte)(digit << 1);
		// STEP n = 7: Read the 4th Char in a 8-chars Subblock
		// Insert 1 bit, leave 4 bits, possibly trailing if no more Char
		if ((digit = (int)chars[charsOffset + 3] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		bytes[bytesOffset + 1] = (Byte)((digit >> 4) | lastDigit);
		lastDigit = (Byte)((digit & 15) << 4);
		if (charsLen == 4) {
			if (lastDigit != 0) return nil; // non-canonical end
			break; // discard the 4 trailing null bits
		}
		// STEP n = 4: Read the 5th Char in a 8-Chars subblock
		// Insert 4 bits, leave 1 bit, possibly trailing if no more Char
		if ((digit = (int)chars[charsOffset + 4] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		bytes[bytesOffset + 2] = (Byte)((digit >> 1) | lastDigit);
		lastDigit = (Byte)((digit & 1) << 7);
		if (charsLen == 5) {
			if (lastDigit != 0) return nil; // non-canonical end
			break; // discard the 1 trailing null bit
		}
		// STEP n = 1: Read the 6th Char in a 8-Chars subblock
		// Leave 6 bits, asserting there's another encoding Char
		if ((digit = (int)chars[charsOffset + 5] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		lastDigit |= (Byte)(digit << 2);
		// STEP n = 6: Read the 7th Char in a 8-Chars subblock
		// Insert 2 bits, leave 3 bits, possibly trailing if no more Char
		if ((digit = (int)chars[charsOffset + 6] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		bytes[bytesOffset + 3] = (Byte)((digit >> 3) | lastDigit);
		lastDigit = (Byte)((digit & 7) << 5);
		if (charsLen == 7) {
			if (lastDigit != 0) return nil; // non-canonical end
			break; // discard the 3 trailing null bits
		}
		// STEP n = 3: Read the 8th Char in a 8-Chars subblock
		// Insert 5 bits, leave 0 bit, next encoding Char may not exist
		if ((digit = (int)chars[charsOffset + 7] - charDigitsBase) < 0 || digit >= charDigitsLen || (digit = charDigits[digit]) == -1)
			return nil; // invalid character
		bytes[bytesOffset + 4] = (Byte)(digit | lastDigit);
		//// This point is always reached for chars.length multiple of 8
		charsOffset += 8;
		bytesOffset += 5;
		charsLen -= 8;
	}
	// On loop exit, discard the n trailing null bits
	return [NSData dataWithBytes:bytes length:sizeof(bytes)];
}

- (NSString *) base32String
{
	/* Lookup table used to canonically encode() groups of data bits */
	static char canonicalChars[] =
	{	'A','B','C','D','E','F','G','H','I','J','K','L','M' // 00..12
		,'N','O','P','Q','R','S','T','U','V','W','X','Y','Z' // 13..25
		,'2','3','4','5','6','7'                             // 26..31
	};
	const Byte *bytes = [self bytes];
	int bytesOffset = 0, bytesLen = [self length];
	int charsOffset = 0, charsLen = ((bytesLen << 3) + 4) / 5;
	char chars[charsLen];
	while (bytesLen != 0) {
		int digit, lastDigit;
		// INVARIANTS FOR EACH STEP n in [0..5[; digit in [0..31[;
		// The remaining n bits are already aligned on top positions
		// of the 5 least bits of digit, the other bits are 0.
		////// STEP n = 0: insert new 5 bits, leave 3 bits
		digit = bytes[bytesOffset] & 255;
		chars[charsOffset] = canonicalChars[digit >> 3];
		lastDigit = (digit & 7) << 2;
		if (bytesLen == 1) { // put the last 3 bits
			chars[charsOffset + 1] = canonicalChars[lastDigit];
			break;
		}
		////// STEP n = 3: insert 2 new bits, then 5 bits, leave 1 bit
		digit = bytes[bytesOffset + 1] & 255;
		chars[charsOffset + 1] = canonicalChars[(digit >> 6) | lastDigit];
		chars[charsOffset + 2] = canonicalChars[(digit >> 1) & 31];
		lastDigit = (digit & 1) << 4;
		if (bytesLen == 2) { // put the last 1 bit
			chars[charsOffset + 3] = canonicalChars[lastDigit];
			break;
		}
		////// STEP n = 1: insert 4 new bits, leave 4 bit
		digit = bytes[bytesOffset + 2] & 255;
		chars[charsOffset + 3] = canonicalChars[(digit >> 4) | lastDigit];
		lastDigit = (digit & 15) << 1;
		if (bytesLen == 3) { // put the last 1 bits
			chars[charsOffset + 4] = canonicalChars[lastDigit];
			break;
		}
		////// STEP n = 4: insert 1 new bit, then 5 bits, leave 2 bits
		digit = bytes[bytesOffset + 3] & 255;
		chars[charsOffset + 4] = canonicalChars[(digit >> 7) | lastDigit];
		chars[charsOffset + 5] = canonicalChars[(digit >> 2) & 31];
		lastDigit = (digit & 3) << 3;
		if (bytesLen == 4) { // put the last 2 bits
			chars[charsOffset + 6] = canonicalChars[lastDigit];
			break;
		}
		////// STEP n = 2: insert 3 new bits, then 5 bits, leave 0 bit
		digit = bytes[bytesOffset + 4] & 255;
		chars[charsOffset + 6] = canonicalChars[(digit >> 5) | lastDigit];
		chars[charsOffset + 7] = canonicalChars[digit & 31];
		//// This point is always reached for bytes.length multiple of 5
		bytesOffset += 5;
		charsOffset += 8;
		bytesLen -= 5;
	}
	return [NSString stringWithCString:chars length:sizeof(chars)];
}

#define FinishBlock(X)  (*code_ptr = (X),   code_ptr = dst++,   code = 0x01)

- (NSData *) encodeCOBS
{
	if ([self length] == 0) return self;
	
	NSMutableData *encoded = [NSMutableData dataWithLength:([self length] + [self length] / 254 + 1)];
	unsigned char *dst = [encoded mutableBytes];
	const unsigned char *ptr = [self bytes];
	unsigned long length = [self length];
	const unsigned char *end = ptr + length;
	unsigned char *code_ptr = dst++;
	unsigned char code = 0x01;
	while (ptr < end)
	{
		if (*ptr == 0) FinishBlock(code);
		else
		{
			*dst++ = *ptr;
			code++;
			if (code == 0xFF) FinishBlock(code);
		}
		ptr++;
	}
	FinishBlock(code);
	
	[encoded setLength:((Byte *)dst - (Byte *)[encoded mutableBytes])];
	return [NSData dataWithData:encoded];
}

- (NSData *) decodeCOBS
{
	if ([self length] == 0) return self;
	
	const Byte *ptr = [self bytes];
	unsigned length = [self length];
	NSMutableData *decoded = [NSMutableData dataWithLength:length];
	Byte *dst = [decoded mutableBytes];
	Byte *basedst = dst;
	
	const unsigned char *end = ptr + length;
	while (ptr < end)
	{
		int i, code = *ptr++;
		for (i=1; i<code; i++) *dst++ = *ptr++;
		if (code < 0xFF) *dst++ = 0;
	}
	
	[decoded setLength:(dst - basedst)];
	return [NSData dataWithData:decoded];
}

- (NSData *)zlibInflate
{
	if ([self length] == 0) return self;
	
	unsigned full_length = [self length];
	unsigned half_length = [self length] / 2;
	
	NSMutableData *decompressed = [NSMutableData dataWithLength: full_length + half_length];
	BOOL done = NO;
	int status;
	
	z_stream strm;
	strm.next_in = (Bytef *)[self bytes];
	strm.avail_in = [self length];
	strm.total_out = 0;
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	
	if (inflateInit (&strm) != Z_OK) return nil;
	
	while (!done)
	{
		// Make sure we have enough room and reset the lengths.
		if (strm.total_out >= [decompressed length])
			[decompressed increaseLengthBy: half_length];
		strm.next_out = [decompressed mutableBytes] + strm.total_out;
		strm.avail_out = [decompressed length] - strm.total_out;
		
		// Inflate another chunk.
		status = inflate (&strm, Z_SYNC_FLUSH);
		if (status == Z_STREAM_END) done = YES;
		else if (status != Z_OK) break;
	}
	if (inflateEnd (&strm) != Z_OK) return nil;
	
	// Set real length.
	if (done)
	{
		[decompressed setLength: strm.total_out];
		return [NSData dataWithData: decompressed];
	}
	else return nil;
}

- (NSData *)zlibDeflate
{
	if ([self length] == 0) return self;
	
	z_stream strm;
	
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	strm.total_out = 0;
	strm.next_in=(Bytef *)[self bytes];
	strm.avail_in = [self length];
	
	// Compresssion Levels:
	//   Z_NO_COMPRESSION
	//   Z_BEST_SPEED
	//   Z_BEST_COMPRESSION
	//   Z_DEFAULT_COMPRESSION
	
	if (deflateInit(&strm, Z_DEFAULT_COMPRESSION) != Z_OK) return nil;
	
	NSMutableData *compressed = [NSMutableData dataWithLength:16384];  // 16K chuncks for expansion
	
	do {
		
		if (strm.total_out >= [compressed length])
			[compressed increaseLengthBy: 16384];
		
		strm.next_out = [compressed mutableBytes] + strm.total_out;
		strm.avail_out = [compressed length] - strm.total_out;
		
		deflate(&strm, Z_FINISH);  
		
	} while (strm.avail_out == 0);
	
	deflateEnd(&strm);
	
	[compressed setLength: strm.total_out];
	return [NSData dataWithData: compressed];
}

- (NSData *)gzipInflate
{
	if ([self length] == 0) return self;
	
	unsigned full_length = [self length];
	unsigned half_length = [self length] / 2;
	
	NSMutableData *decompressed = [NSMutableData dataWithLength: full_length + half_length];
	BOOL done = NO;
	int status;
	
	z_stream strm;
	strm.next_in = (Bytef *)[self bytes];
	strm.avail_in = [self length];
	strm.total_out = 0;
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	
	if (inflateInit2(&strm, (15+32)) != Z_OK) return nil;
	while (!done)
	{
		// Make sure we have enough room and reset the lengths.
		if (strm.total_out >= [decompressed length])
			[decompressed increaseLengthBy: half_length];
		strm.next_out = [decompressed mutableBytes] + strm.total_out;
		strm.avail_out = [decompressed length] - strm.total_out;
		
		// Inflate another chunk.
		status = inflate (&strm, Z_SYNC_FLUSH);
		if (status == Z_STREAM_END) done = YES;
		else if (status != Z_OK) break;
	}
	if (inflateEnd (&strm) != Z_OK) return nil;
	
	// Set real length.
	if (done)
	{
		[decompressed setLength: strm.total_out];
		return [NSData dataWithData: decompressed];
	}
	else return nil;
}

- (NSData *)gzipDeflate
{
	if ([self length] == 0) return self;
	
	z_stream strm;
	
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	strm.total_out = 0;
	strm.next_in=(Bytef *)[self bytes];
	strm.avail_in = [self length];
	
	// Compresssion Levels:
	//   Z_NO_COMPRESSION
	//   Z_BEST_SPEED
	//   Z_BEST_COMPRESSION
	//   Z_DEFAULT_COMPRESSION
	
	if (deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, (15+16), 8, Z_DEFAULT_STRATEGY) != Z_OK) return nil;
	
	NSMutableData *compressed = [NSMutableData dataWithLength:16384];  // 16K chunks for expansion
	
	do {
		
		if (strm.total_out >= [compressed length])
			[compressed increaseLengthBy: 16384];
		
		strm.next_out = [compressed mutableBytes] + strm.total_out;
		strm.avail_out = [compressed length] - strm.total_out;
		
		deflate(&strm, Z_FINISH);  
		
	} while (strm.avail_out == 0);
	
	deflateEnd(&strm);
	
	[compressed setLength: strm.total_out];
	return [NSData dataWithData:compressed];
}

// --------------------------------CRC32-------------------------------
static const unsigned long crc32table[] =
{
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

- (unsigned int)crc32
{
	unsigned int	crcval;
	unsigned int	x, y;
	const void		*bytes;
	unsigned int    max;
	
	bytes = [self bytes];
	max = [self length];
	crcval = 0xffffffff;
	for (x = 0, y = max; x < y; x++) {
		crcval = ((crcval >> 8) & 0x00ffffff) ^ crc32table[(crcval ^ (*((unsigned char *)bytes + x))) & 0xff];
	}
	
	return crcval ^ 0xffffffff;
}

// Hash function, by DamienBob

#define HEComputeDigest(method)						\
method##_CTX ctx;								\
unsigned char digest[method##_DIGEST_LENGTH];		\
method##_Init(&ctx);							\
method##_Update(&ctx, [self bytes], [self length]);		\
method##_Final(digest, &ctx);

#define HEComputeDigestNSData(method)				\
HEComputeDigest(method)						\
return [NSData dataWithBytes:digest length:method##_DIGEST_LENGTH];

#define HEComputeDigestNSString(method)				\
static char __HEHexDigits[] = "0123456789abcdef";		\
unsigned char digestString[2*method##_DIGEST_LENGTH];	\
unsigned int i;									\
HEComputeDigest(method)						\
for(i=0; i<method##_DIGEST_LENGTH; i++) {				\
	digestString[2*i]   = __HEHexDigits[digest[i] >> 4];	\
	digestString[2*i+1] = __HEHexDigits[digest[i] & 0x0f];\
}											\
return [NSString stringWithCString:(char *)digestString length:2*method##_DIGEST_LENGTH];

#define SHA1_CTX				SHA_CTX
#define SHA1_DIGEST_LENGTH		SHA_DIGEST_LENGTH

- (NSData*) md5Digest
{
	HEComputeDigestNSData(MD5);
}

- (NSString*) md5DigestString
{
	HEComputeDigestNSString(MD5);
}

- (NSData*) sha1Digest
{
	HEComputeDigestNSData(SHA1);
}

- (NSString*) sha1DigestString
{
	HEComputeDigestNSString(SHA1);
}

- (NSData*) ripemd160Digest
{
	HEComputeDigestNSData(RIPEMD160);
}

- (NSString*) ripemd160DigestString
{
	HEComputeDigestNSString(RIPEMD160);
}

- (NSString *)hexString;
{
	const unsigned char *bytes = [self bytes];
	NSMutableString *hexString = [[[NSMutableString alloc] initWithCapacity:[self length] * 2] autorelease];
	for (int i = 0; i < [self length]; i++)
		[hexString appendFormat:@"%02x", (unsigned char)(bytes[i])];
	return [hexString uppercaseString];
}

+ (NSData *)dataWithHexString:(NSString *)hexString;
{
	NSMutableData *data = [NSMutableData dataWithCapacity:[hexString length]/2];
	char *chars = (char *)[hexString UTF8String];
	unsigned char value;
	while (*chars != '\0') {
		if (*chars >= '0' && *chars <= '9')
			value = (*chars - '0') << 4;
		else if (*chars >= 'a' && *chars <= 'f')
			value = (*chars - 'a' + 10) << 4;
		else if (*chars >= 'A' && *chars <= 'F')
			value = (*chars - 'A' + 10) << 4;
		else
			return nil;
		
		chars++;
		if (*chars >= '0' && *chars <= '9')
			value |= *chars - '0';
		else if (*chars >= 'a' && *chars <= 'f')
			value |= *chars - 'a' + 10;
		else if (*chars >= 'A' && *chars <= 'F')
			value |= *chars - 'A' + 10;
		else
			return nil;
		[data appendBytes:&value length:sizeof(value)];
		chars++;
	}
	return data;
}

+ (NSData *)dataWithString:(NSString *)string;
{
	const char *bytes = [string UTF8String];
	return [NSData dataWithBytes:bytes length:strlen(bytes)];
}

+ (NSData *)dataWithStringNoNull:(NSString *)string;
{
	const char *bytes = [string UTF8String];
	size_t lengthWithoutNull = strlen(bytes)-1;
	if (lengthWithoutNull <= 0)
		return nil;
	return [NSData dataWithBytes:bytes length:lengthWithoutNull];
}


@end
